1. Field of the Invention
The present invention relates to a method and apparatus for identical head- and centric block related incorporation of jaw models into the most common articulator system.
2. Description of the Related Art
In the field or prosthetics, ground and bridge technique as well as in the frame work of functional diagnostics, after taking pressure forms from the patient, jaw models are prepared and incorporated or articulated into so-called articulators.
Thereby these apparatuses simulate the movement of the jaw of the patient, whereby in addition to the pure opening and closing movement of the lower jaw via a rotation axis by means of both jaw hinge heads, forward and sideward movements can also be simulated.
Naturally such a simulation can take place only more or less exactly, whereby the articulator type determines, which information content from the patient can be entered to simulate the jaw movement. The extent of this information entering decides also about which information content the apparatus can give back and/or by which information content prosthetic work prepared therein can be codetermined.
In the case of more demanding, partially adjustable articulators, in particular with fully adjustable apparatuses, the head-related upper jaw incorporation is obligatory. In other words, the upper jaw model in its special situation to the artificial jaw hinges of the articulator is incorporated in such a way as corresponds closely to the case of the patient. In practice, this is made possible by a so-called "face arc", which takes the position of the upper jaw in relation to the jaw hinges and to a deliberately determined plane, e.g., the hinged axis-orbital plane. In the case of some types of apparatuses it is possible to adjust to this plane further reference parameters such as hinge tour bending or the Bennett-angle.
The lower jaw model incorporation takes place via a so-called centric block registrate, whereby the patient preferably bites into a wax piece. Afterwards, with the help of the dentist or orthodontist, the lower jaw is laid into the so-called centric jaw hinge position or the terminal hinge axis position.
If a prosthetic work requires, for example, a bite lifting then this takes place in practical laboratory practice, in that after upper and lower jaw model incorporation the articulator is opened to the desired extent by hinge movement via its rotation axis.
It is natural that in the case of this procedure, mistakes necessarily occur, if the arrangement of the upper jaw model to the articulator rotation axis shows a relation other than the corresponding relation at the patient.
In the case of the utilized face arc types only few apparatuses are compatible with different articulator systems. This means that the dentist has commit himself in the case of a planned head-related model incorporation to an articulator type and thus has to commit the corresponding face arc. Accordingly, the laboratory which constructs the prosthetic piece is committed to this articulator type.
However, all common articulator systems function principally similarly, whereby gypsum carrier plates are premounted and connected with the models by means of a gypsum base.
Different articulators differ from each other in the building height, the arrangement of the artificial jaw hinges and in the dimensions of the gypsum carriers.
Articulators are comparable to computers since they, as described above, deliver information, if they are first fed with information.
In normal routine work, partially adjustable articulators suffice in which a few parameters, such as, for example, the hinge bending or the so-called Bennett-angle, are predetermined.
In the case of fully adjustable articulators, parameters can be individually entered besides other parameters. In the case of partially adjustable apparatuses, there already exists in many cases the possibility of a head-related upper jaw incorporation.
According to the design of the respective articulator upper jaw are consequently for the different articulator systems, a gypsum base of different height results. The building height of the articulator determines, after the arrangement of the lower jaw model to the built-in upper jaw model, the height of the lower jaw gypsum base.
The possibility to utilize two apparatuses simultaneously without new mounting, that is, the transferability of a premounted model from one apparatus to another, which can be of importance in work with an outside laboratory, is so far known only with the same type of articulator.